1. Field of the Invention
The present invention relates to a virtual image display apparatus having a function of display of a magnified virtual image, for visually magnifying and displaying an image to be monitored, and also relates to an electronic equipment using thereof.
2. Description of Related Art
These years, various information processing equipments, and in particular, equipments which can process visual information by means of liquid crystal or photoelectric image display means or the like, have been astonishingly progressed. The so-called mobile equipments, that is, data processing machines which can be personally used at any of various places, have also remarkably developed. The mobile equipments are desirable so as to have a compact body for portability, a high speed of data processing, several processing functions, and as well to have a means for precisely and straightforward displaying much more information to the user within a limited space of a small-sized equipment. Display means which utilizes liquid crystal or the like and which occupies a substantial part of the operating surface of an equipment has been prosperously used as such an image displaying means, but it can hardly have a possibility of follow-up of miniaturization of the equipment.
Accordingly, in order to effectively solve the above-mentioned problems, for example, virtual image magnifying and displaying units including head-mounting displays and finder (check) displays have been become noticeable, and accordingly, various studies and the development of associated equipments have been made until now.
The virtual image magnifying and displaying device is configured such that a single lens or a combination of a plurality of lenses is used so as to project a virtual image which is magnified by a positive refractive power, in the visual field. The structure thereof is simple, and has been prosperously used in general for optical systems having a relative small viewing angle. For example, it is used in a monitoring finder optical system for setting the photographing range (viewing angle) and confirming the focusing, among many video camera recorders. However, it has been raised such a problem that the structure becomes larger in the direction of the optical axis of the optical system.
In an example of another arrangement using a half-mirror, the brightness of a virtual image is lowered, and accordingly, the virtual image displaying apparatus exhibits a very dark virtual image to the eyes of the user, that is, the visibility of the virtual image is low. Further, the higher the brightness of the image, the larger the power for the illumination, the power consumption is increased, and accordingly, the virtual image display unit becomes unsuitable for portable data terminals.